Door-spring



(No Model.)

J. P. HARRISON.

DOOR SPRING. y N0. 376,435. Patented Jan. 17, 1888.

.dttorney UNITED STATES PATENT OFFICE.

Y JAMES P. HARRISON, OF DANVIDLE, VIRGlNIA.

DOOR-SPRING.

SPECIFICATION forming part of Letters Patent No. 376,435, dated January 17-l 1888.

Application filed April 20, 1887.

.To @ZZ whom it may concern:

Be it known that I, JAMES P. HARRISON, a citizen of the United States, residing at Danville, in the county of Pittsylvania, State of Virginia, have invented certain new and useful Improvements in Door-Springs, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to improvements in door-springs.

The object of my invention is to provide a cheap and reliable spring whichwill close the door at all times without slamming, as will more fully hereinafter appear.

Referring to the drawings, Figure 1 is a View in elevation of a door and door-frame with my improved spring secured thereto. Fig. 2 is a front view of my improved spring. Fig. 3 is a sectional end View of the springcontaining block, showing a dovetailed groove for thereception of a dovetailed block. Fig. 4 is a seetional plan view showing a bolt for lockingthe sliding block until the springs arein alignment, when the bolt will be disengaged and the block released.

A indicates a block which is secured to the door B near the hinged side, and in the face of said block is formed a dovetailed groove, C, said groove being designed to receive a dovetailed block, D, adapted to move back and forth in said groove. y

E is a spiral spring, one end of which is secured to the block A at the end of the dovetailed groove and adapted to lie in said groove, while the other'end of said spring is secured to the front end of the sliding block D.

F is aspiral spring, one end of which is secured to the sliding block D, while the other end is attached or secured to the block G,which in turn is secured to the casing of the door H.

The operation of my improved spring is as follows: W-hen the door isbeing opened, the spring F is extended and the sliding block is drawn toward the rear end of the dovetailed groove. 'Ih'e tension of this spring when'ihe door is being opened is at an angle to the groove C, which tends to pull the sliding block forward, and the frictional contact of the block with the sides of the groove prevents said block from moving to any great extent in the groove Serial N0.235,493. (No model.)

until the spring F is on a line parallel with the' groove O. At this point the block D is drawn toward the rear end of the groove by the spring F, but its movement is resisted by the spring E, said spring being distended as the block' D is forced back by the continued pressure exerted in opening the door. When the door is released, the recoil of the spring F allows the block to be drawn back in the slot `C by the tension of the spring E.

The opening of the door does not distend the spring E to any great extent until it is opened beyond the exact alignment. When the spring F does little work, E comes into play, so that when the force of the spring F has been expended and the tension of the spring E has been relaxed said spring will act as a buffer to prevent the further forward movement of the block D, and in this way the door is freed from the action of thesprings and prevented from being brought too rapidly against the casing of the door.

It is not essential that the groove should be dovetailed; but any kind of slot or groove may be used which will answer the purpose.

ln some cases lthe groove in the block Amay be provided with notches and the block D with proj eetions on its top to tit into the notches .i in the groove, so that the block A will be held in position by the direct strain of the spring F until said springF is brought into alignment and exerts its power in the direction of the length oi the block A. Then the spring E will have a tendency to draw the block D down to the bottom of the groove and release it from the notches, thus transferring a portion.

of the strain exerted on the spring F to the spring E, and in this manner divide the strain.

In Fig. 4 I have shown a modification in which the block D is held bya bolt, A', which engages with a hole, a, in the bottom of the IOO any suitable device for tightening them when dovetailed grooved block A, sliding block D, they become weakened by constant or oonfttng within the groove, spring F, secured to tinued use. the sliding block and to the door-frame, and

Having thus described my invention, whatI the spring E, also secured to the sliding block claim, and desire to secure by Letters Patent, and to the grooved block A, all substantially isas and for the purpose set forth.

1. In a door-spring, a block to slide or be In testimony whereofIufx my signaturein moved in ways on the door or casing, in eompresence of two witnesses. bination with springs to act upon the block JAMES I. HARRISON. upon both sides and in both directions, substantially as set forth.

2. In :1 door-spring, the combination of the Witnesses:

P. R. BERKELEY, N. W. BERKELEY, J r. 

